Titanium-containing welding wire steel bar for marine equipment and preparation method of titanium-containing welding wire steel bar

Abstract

The invention relates to the field of metallurgy, and discloses a titanium-containing welding wire steel bar for marine equipment and a preparation method of the titanium-containing welding wire steel bar. The titanium-containing welding wire steel bar is prepared through vacuum induction melting, electroslag remelting smelting and forging and comprises 0.03%-0.09% of C, 0.40%-0.80% of Si, 1.00%-1.60% of Mn, smaller than or equal to 0.006% of P, smaller than or equal to 0.005% of S, 0.20%-1.00% of Cr, 0.50%-1.00% of Mo, 0.50%-1.00% of Ni, 0.05%-1.00% of Ti, 0.002%-0.010% of Zr, smaller than or equal to 45 PPm of [O], smaller than or equal to 45 PPm of [N] and the balance iron and impurity elements. Through steel component design and technological parameter control, the high-purity welding wire steel bar with the uniform and compact structure is prepared, and favorable conditions are provided for preparing the high-purity welding wire with the excellent structure performance in the next step.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a titanium-containing welding wire steel bar for marine equipment and a preparation method thereof. Background Art

[0002] At present, the activities of countries around the world in searching for oil and natural gas at sea are developing from shallow waters to deep seas. With the continuous expansion of surveys and explorations for oil and natural gas in the ocean, the shipbuilding and offshore engineering industries have developed rapidly, and high-strength and low-temperature steels containing alloy elements such as Ni, Cr and Mo have been widely used. This type of steel needs to meet the requirements of high strength, high toughness, resistance to lamellar tearing and corrosion resistance at the same time. This type of steel is usually welded with imported flux-cored gas shielded welding wire, which is not only expensive, but also has a long supply cycle, which restricts the development of the industry. Therefore, the development of solid welding wire suitable for high-strength offshore steel welding to replace the long-term dependent flux-cored welding wire is the development trend of domestic offshore steel supporting welding materials.

[0003] At present, the welding wire steel billets at home and abroad are basically produced by the process of "electric furnace / converter steelmaking + LF refining + vacuum treatment + continuous casting of small square billets + continuous rolling", but for the steel used in marine special equipment, it is required to meet the requirements of high strength, high toughness, lamellar tearing resistance and corrosion resistance at the same time. In order to meet the strength and low-temperature impact toughness requirements of the weld, it is necessary to add trace amounts of Cr, Mo, Ni and Ti for micro-alloying treatment during the composition design, and at the same time, strict deep dephosphorization, sulfur removal and strong deoxidation are required during smelting. In addition, in order to achieve the uniformity of the structure of the weld area, higher requirements are put forward for the uniformity of the longitudinal and transverse structures of the steel billets for welding wire. Therefore, it is of great significance to study the forming process of steel billets for welding wire, provide solid steel billets for welding wire with excellent structure and performance for the next step of rolling coils and drawing, meet the domestic marine special equipment supporting welding materials, and replace the flux-cored welding wire that has long relied on imports. Summary of the invention

[0004] The main purpose of the present invention is to provide a titanium-containing welding wire steel bar for marine equipment and a preparation method thereof, so as to obtain a solid welding wire with excellent organizational properties for marine equipment by the next step of rolling and drawing deformation, thereby solving the problem that domestic special marine equipment welding wire steel has long relied on imported flux-cored welding wire.

[0005] To achieve the above object, the present invention adopts the following technical solutions: According to one aspect of the present invention, a titanium-containing welding wire steel bar for marine equipment is provided. The titanium-containing welding wire steel bar comprises, by mass percentage: C: 0.03~0.09%, Si: 0.40~0.80%, Mn: 1.00~1.60%, P≤0.006%, S≤0.005%, Cr: 0.20~1.00%, Mo: 0.50~1.00%, Ni: 0.50~1.00%, Ti: 0.05~1.00%, Zr: 0.002~0.010%, [O]≤45PPm, [N]≤45PPm, and the rest are iron and impurity elements.

[0006] According to another aspect of the present invention, a method for preparing a titanium-containing welding wire steel bar for marine equipment is provided, which is used to prepare the above-mentioned titanium-containing welding wire steel bar. The preparation method comprises: sequentially performing vacuum induction melting, electroslag remelting smelting, and forging to obtain the titanium-containing welding wire steel bar, wherein: The vacuum induction melting comprises batching, vacuum induction furnace melting and pouring in sequence to obtain an electrode rod, wherein: in the batching process, according to the mass percentage of the elements of the titanium-containing welding wire steel rod, carbon blocks, metal silicon, metal manganese, metal chromium, metal molybdenum, metal nickel, titanium-iron alloy, metal zirconium and pure iron are weighed as raw materials; in the vacuum induction furnace melting process, pure iron, metal chromium, metal molybdenum and metal nickel are loaded into the vacuum induction furnace, and power melting is started when the vacuum degree is ≤10Pa, and the temperature is adjusted to 1580-1620°C after melting, and carbon blocks are added when the vacuum degree is ≤5Pa, and the refining time is ≥30min under stirring conditions, and then inert gas is filled, and metal silicon, metal manganese and titanium-iron alloy are added, and the homogenization time is ≥10min under stirring conditions, and finally metal zirconium is added, and the homogenization time is ≥5min under stirring conditions to obtain an alloy melt; in the pouring process, the alloy melt is poured into an electrode rod, The electroslag remelting smelting includes sequentially performing electrode rod surface treatment and protective atmosphere electroslag remelting smelting to obtain electroslag ingots, wherein: during the electrode rod surface treatment process, the electrode rod surface is polished; during the protective atmosphere electroslag remelting smelting process, a CaF2-CaO-Al2O3-TiO2 slag system is used, the slag heating temperature is 1050-1300°C, the slag time is 40-90min, the voltage is controlled at 100-40V, the current is controlled at 30000-8000A, the average melting rate is controlled at 5.0-10.0kg / min, and the shrinkage feeding time is ≥30min. The forging process includes sequentially performing electroslag ingot heating, blank forming, furnace heating, fine forging and air cooling to obtain the titanium-containing welding wire steel bar, wherein: during the electroslag ingot heating process and the furnace heating process, the heating temperature is 1100-1250°C, and the insulation time is calculated according to the diameter of the electroslag ingot; during the blank forming process, a one-upsetting-one-drawing process is adopted, and the final forging temperature is ≥800°C; during the fine forging process, the final forging temperature is ≥800°C.

[0007] According to some embodiments of the present invention, before the vacuum induction furnace smelting process, the chute is heated in a heating furnace at 1100-1200° C., and the insulation time is greater than 3 hours.

[0008] According to some embodiments of the present invention, before the batching process, pure iron, metal chromium, metal molybdenum, and metal nickel are subjected to sandblasting.

[0009] According to some embodiments of the present invention, during the vacuum induction furnace smelting process, after power smelting starts, the charge is first melted at a first power, and after the molten steel covers the bottom of the crucible, the power is switched to a second power, and the first power is greater than the second power.

[0010] According to some embodiments of the present invention, during the smelting process in a vacuum induction furnace, the vacuum degree is ≤5Pa.

[0011] According to some embodiments of the present invention, during the vacuum induction furnace smelting process, the total refining time is ≥ 1 h.

[0012] According to some embodiments of the present invention, during the pouring process, the pouring temperature of the electrode rod is 1550~1580°C, the pouring speed at the beginning of pouring is 20~50kg / s, after pouring 1 / 4 of the ingot body height, the remaining ingot body is poured at a pouring speed of 50~100kg / s, and the riser pouring is poured at a pouring speed of 2~10kg / s.

[0013] According to some embodiments of the present invention, after pouring is completed, air breaking and demoulding are performed, and the air breaking time is ≥100 minutes and the demolding time is ≥240 minutes.

[0014] According to some embodiments of the present invention, in the CaF2-CaO-Al2O3-TiO2 slag system, the mass ratio of each substance is: CaF2:CaO:Al2O3:TiO2 is 64%:20%:15%:1%.

[0015] According to some embodiments of the present invention, during the electroslag remelting process in a protective atmosphere, C powder, Al particles and Si-Ca powder are used to deoxidize, fine-tune the composition and mitigate the burning loss of the original composition of the billet.

[0016] According to some embodiments of the present invention, during the electroslag remelting process in a protective atmosphere, the temperature of the cooling water of the crystallizer is ≤55°C.

[0017] According to some embodiments of the present invention, after the protective atmosphere electroslag remelting smelting is completed, air breaking and demolding treatment is performed, and the air breaking time is ≥120 minutes and the mold moving time is ≥360 minutes.

[0018] According to some embodiments of the present invention, during the heating process of the electroslag ingot, the heating rate is ≤80°C / s.

[0019] According to some embodiments of the present invention, during the heating process of the electroslag ingot, the holding time is calculated according to the following formula: T=KD, where K is the holding time coefficient, with a value of 0.1-1.5, and D is the diameter of the electroslag ingot.

[0020] According to some embodiments of the present invention, the heating temperature and the holding time of the reheating process are the same as the heating temperature and the holding time of the electroslag ingot heating process.

[0021] According to some embodiments of the present invention, during the blank forming process, the upsetting ratio is greater than 3.5, and the reduction amount of at least one pass during the drawing process should be greater than or equal to 20%.

[0022] According to some embodiments of the present invention, during the precision forging process, four-hammer deformation is adopted, the forging hammer striking frequency is ≥90 times / min, and the billet feeding speed is ≤25mm / s.

[0023] According to some embodiments of the present invention, the cooling process is implemented in a chain cooling bed.

[0024] Due to the adoption of the above technical solution, the present invention has at least the following effective effects: In the present invention, by adopting vacuum induction melting + electroslag remelting smelting process, a high-purity, uniform and dense steel ingot for welding wire is obtained, wherein [O]≤45PPm, [N]≤45PPm, P≤0.006%, S≤0.005%; by adopting upsetting + drawing + fine forging process, the anisotropy of the structure is reduced, and a welding wire steel bar with uniform structure is obtained, which provides favorable conditions for the next step of preparing high-purity welding wire with excellent structure and performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A flow chart showing a method for preparing a titanium-containing welding wire steel bar for marine equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0028] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0029] According to one aspect of the present invention, a titanium-containing welding wire steel bar for marine equipment is provided. The titanium-containing welding wire steel bar comprises, by mass percentage: C: 0.03~0.09%, Si: 0.40~0.80%, Mn: 1.00~1.60%, P≤0.006%, S≤0.005%, Cr: 0.20~1.00%, Mo: 0.50~1.00%, Ni: 0.50~1.00%, Ti: 0.05~1.00%, Zr: 0.002~0.010%, [O]≤45PPm, [N]≤45PPm, and the rest are iron and impurity elements.

[0030] In the present invention, a micro-alloying treatment is performed by adding trace amounts of Mn, Cr, Mo, Ni, Ti and Zr in the composition design to meet the high strength and low temperature impact toughness requirements of marine equipment.

[0031] According to another aspect of the present invention, a method for preparing the titanium-containing welding wire steel bar for marine equipment is provided, such as Figure 1 As shown, the method includes: sequentially performing vacuum induction melting, electroslag remelting, and forging to obtain titanium-containing welding wire steel bars.

[0032] The vacuum induction melting includes batching, vacuum induction furnace melting and pouring in sequence to obtain an electrode rod. In the batching process, carbon blocks, metal silicon, metal manganese, metal chromium, metal molybdenum, metal nickel, titanium iron alloy, metal zirconium and pure iron are weighed as raw materials according to the mass percentage of the elements of the titanium-containing welding wire steel bar. In the present invention, in order to prepare a high-purity titanium-containing welding wire steel bar, the content of harmful elements introduced into the raw materials is strictly controlled by selecting the raw materials. During the vacuum induction furnace smelting process, pure iron, metal chromium, metal molybdenum and metal nickel are loaded into the vacuum induction furnace, and electric smelting is started when the vacuum degree is ≤10Pa. After melting, the temperature is adjusted to 1580-1620°C (typically but not limitatively, it can be 1580°C, 1585°C, 1590°C, 1595°C, 1600°C, 1605°C, 1610°C, 1615°C, 1620°C), and carbon blocks are added when the vacuum degree is ≤5Pa. The refining time under stirring conditions is ≥30min (typically but not limitatively, it can be 30min, 35min, 40min, 45min, 50min, 60min, 70min, 80min, 90min, 10 ... min, 55min, etc.), then fill with inert gas, add metal silicon, metal manganese, and titanium iron alloy, and homogenize for ≥10min under stirring conditions (typically but not limited to, 10min, 15min, 20min, 25min, 30min, 35min, 40min, etc.), and finally add metal zirconium, and homogenize for ≥5min under stirring conditions (typically but not limited to, 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, etc.) to obtain an alloy melt. During the casting process, the alloy melt is cast into an electrode rod.

[0033] The electroslag remelting smelting includes sequentially performing electrode rod surface treatment and protective atmosphere electroslag remelting smelting to obtain electroslag ingots. During the electrode rod surface treatment process, the electrode rod surface is polished to remove surface oxide scale and attachments. In the protective atmosphere electroslag remelting smelting process, a CaF2-CaO-Al2O3-TiO2 slag system is used, the slag heating temperature is 1050-1300°C (typically but not limitatively, the slag heating temperature can be 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C), the slag time is 40-90min (typically but not limitatively, the slag time can be 40min, 50min, 60min, 70min, 80min, 90min, etc.), the voltage is controlled at 100-40V (typically but not limitatively, the voltage can be 100V, 90V, 80V, 70V, 60V, 50V, 40V), and the current is 3 The average melting rate is controlled at 5.0-10.0 kg / min (typically but not limitatively, the average melting rate can be 5.0 kg / min, 6.0 kg / min, 7.0 kg / min, 8.0 kg / min, 9.0 kg / min, 10.0 kg / min), and the feeding time is ≥30 min (typically but not limitatively, the feeding time can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, etc.).

[0034] The forging process includes sequentially performing electroslag ingot heating, blank forming, furnace heating, fine forging and air cooling to obtain titanium-containing welding wire steel bars. During the electroslag ingot heating process and furnace heating process, the heating temperature is 1100~1250℃ (typically but not restrictively, the heating temperature can be 1100℃, 1150℃, 1200℃, 1250℃, etc.), and the holding time is calculated according to the diameter of the electroslag ingot; during the blank forming process, a one-upsetting-one-drawing process is adopted, and the final forging temperature is ≥800℃; during the fine forging process, the final forging temperature is ≥800℃.

[0035] In some embodiments, before the batching process, pure iron, metal chromium, metal molybdenum, and metal nickel are sandblasted to remove surface oxides and attachments, and then batched according to chemical composition requirements.

[0036] In some embodiments, before the vacuum induction furnace smelting process, the chute is heated in a heating furnace at 1100-1200° C. for a holding time of more than 3 hours.

[0037] In some embodiments, during the vacuum induction furnace smelting process, after power smelting starts, the charge is first melted at a first power, and after the molten steel covers the bottom of the crucible, the second power is switched, and the first power is greater than the second power.

[0038] In some embodiments, during the vacuum induction furnace melting process, the vacuum degree is ≤5Pa.

[0039] In some embodiments, during the vacuum induction furnace smelting process, the total refining time is ≥ 1 h.

[0040] In some embodiments, during the pouring process, the pouring temperature of the electrode rod is 1550-1580°C (typically but not limitingly, the pouring temperature may be 1550°C, 1555°C, 1560°C, 1565°C, 1570°C, 1575°C, 1580°C), the pouring speed at the beginning of pouring is 20-50kg / s (typically but not limitingly, the pouring speed may be 20kg / s, 30kg / s, 40kg / s, 50kg / s), and after pouring 1 / 4 of the ingot body, the pouring speed is increased at 50 The rest of the ingot is poured at a pouring speed of 2-10kg / s (typically but not limitedly, the pouring speed can be 2kg / s, 3kg / s, 4kg / s, 5kg / s, 6kg / s, 7kg / s, 8kg / s, 9kg / s, 10kg / s), and the riser pouring is poured at a pouring speed of 2-10kg / s (typically but not limitedly, the pouring speed can be 2kg / s, 3kg / s, 4kg / s, 5kg / s, 6kg / s, 7kg / s, 8kg / s, 9kg / s, 10kg / s).

[0041] In some embodiments, after pouring, air breaking and demolding are performed, the air breaking time is ≥100 min, and the demolding time is ≥240 min (typically but not limitingly, the air breaking time can be 100 min, 150 min, 200 min, 250 min, 300 min, 350 min, 400 min, etc., and the demolding time can be 240 min, 300 min, 360 min, 420 min, 480 min, 540 min, etc.). The purpose of the air breaking treatment is to avoid secondary oxidation of molten steel.

[0042] In some embodiments, in the CaF2-CaO-Al2O3-TiO2 slag system, the mass ratio of each substance is: CaF2:CaO:Al2O3:TiO2 is 64%:20%:15%:1%.

[0043] In some embodiments, during the electroslag remelting process in a protective atmosphere, C powder, Al particles and Si-Ca powder are used to deoxidize, fine-tune the composition and slow down the burning of the original composition of the billet.

[0044] In some embodiments, during the protective atmosphere electroslag remelting process, the temperature of the cooling water of the crystallizer is ≤55°C (typically but not limitingly, the temperature of the cooling water of the crystallizer can be 55°C, 50°C, 45°C, 40°C, 35°C, 30°C, etc.).

[0045] In some embodiments, after the protective atmosphere electroslag remelting smelting is completed, breaking air and demolding treatment is carried out, and the breaking air time is ≥120 minutes, and the moving mold time is ≥360 minutes (typically but not limitatively, the breaking air time can be 120 minutes, 180 minutes, 240 minutes, 300 minutes, 360 minutes, 420 minutes, 480 minutes, etc., and the moving mold time can be 360 ​​minutes, 480 minutes, 540 minutes, 600 minutes, etc.).

[0046] In some embodiments, during the electroslag ingot heating process, the heating rate is ≤80°C / s (typically but not limitingly, the heating rate can be 80°C / s, 75°C / s, 70°C / s, 65°C / s, 60°C / s, 55°C / s, 55°C / s, etc.).

[0047] In some embodiments, during the heating process of the electroslag ingot, the holding time is calculated according to the following formula: T=KD, where K is the holding time coefficient, with a value of 0.1-1.5, and D is the diameter of the electroslag ingot.

[0048] In some embodiments, the heating temperature and the holding time of the reheating process are the same as the heating temperature and the holding time of the electroslag ingot heating process.

[0049] In some embodiments, during the blanking process, the upsetting ratio is greater than 3.5, and the reduction amount of at least one pass during the drawing process should be greater than or equal to 20%.

[0050] In some embodiments, during the precision forging process, four-hammer deformation is used, the forging hammer striking frequency is ≥90 times / min, and the billet feeding speed is ≤25mm / s.

[0051] In some embodiments, the cooling process is carried out in a chain cooling bed.

[0052] In summary, the present invention prepares high-purity, uniform and dense welding wire steel bars through steel composition design and process parameter control, which provides favorable conditions for the next step of preparing high-purity, excellent structural performance welding wire.

[0053] The solution of the present invention is described below based on specific embodiments.

[0054] Example 1 Preparation of Φ100mm H08MnTi welding wire steel bar for marine engineering by the method of the present invention This embodiment adopts 6t vacuum induction furnace + argon protection atmosphere electroslag furnace + 3150t free forging + 1800t precision forging to produce Φ100mm H08Mn welding wire steel bar for marine engineering, specifically: Step 1: Vacuum Induction Melting 1. Dry the chute in a heating furnace at 1100℃~1200℃, and keep it warm for more than 3h; 2. First, pure iron, metal chromium, metal molybdenum and metal nickel are sandblasted, and then the materials are prepared according to the following chemical composition: C 0.05% per furnace, Si: 0.65%, Mn: 1.25%, Cr: 0.50%, Mo: 0.82%, Ni: 0.55%, Ti: 0.08%, Zr: 0.008%, and the rest are iron and impurity elements; 3. Install three Φ360mm steel ingot molds in the vacuum chamber, start to evacuate, and start to supply power when the vacuum degree is ≤10Pa; 4. Specific requirements for smelting process: First melt the charge at high power, turn to low power after the molten steel covers the bottom of the crucible, adjust the temperature to 1590~1610℃ after melting, start adding carbon blocks when the vacuum degree is ≤5Pa, smelt for 50min under high power stirring, then fill with argon, add metal silicon, metal manganese, and ferrotitanium, homogenize for 12min under stirring, finally add metal zirconium, homogenize for 5min under stirring, adjust the temperature to 1560~1570℃ for steel pouring; 5. When pouring each ingot mold, slow pouring is adopted, with a pouring speed of 20~30kg / s. After pouring 1 / 4 of the ingot body, the rest of the ingot body is poured quickly at 50~80kg / s, and the riser pouring is poured at a slow speed of 2~6kg / s; 6. After keeping the temperature in the vacuum furnace for 120 minutes, open the furnace door and break the air; after 240 minutes, start to move the mold, and take component samples after cooling. The [O] content is 22PPm, and the [N] content is 18PPm.

[0055] Step 2: Electroslag remelting 1. Remove the iron oxide and attachments on the surface of the electrode rod, then weld two electrode rods into one electrode, and finally weld the dummy electrode; 2. Install a Φ550mm crystallizer in the electroslag furnace, prepare the slag system according to CaF2:CaO:Al2O3:TiO2=64%:20%:15%:1%, and the total slag volume is 320kg; 3. Rotate the electrode to the smelting station, then evacuate the vacuum, and start power supply after the vacuum degree is ≤20Pa; 4. Increase the current and voltage, heat the furnace temperature to 1100±10℃ to melt the slag, and the slag melting time is 45 minutes; 5. Fill the furnace with argon gas, increase the current and voltage, and start melting the electrode rods. The melting system is: the voltage is controlled at 60~40V, the current is controlled at 16000A~9000A, the average melting speed is controlled at 5.0~7.0kg / min, and the shrinkage time is 50min; 6. During the electroslag remelting process, C powder, Al particles and Si-Ca powder are used to deoxidize, fine-tune the composition and slow down the burning of the original composition of the billet; 7. During the electroslag remelting process, check that the temperature of the cooling water of the crystallizer should be ≤50℃; 8. When the length of the electrode rod tail is 30mm, stop smelting, keep the furnace warm for 180min and then break the air, demould after 360min, and obtain the electroslag steel ingot with the required composition after demoulding, including [O]28PPm, [N]25PPm, P≤0.004%, S≤0.001%.

[0056] Step 3: Forging 1. Heat the electroslag ingot. The heating conditions are: heating to 1150±10℃ at a feeding rate of ≤80℃ / s and keeping temperature for 6h; 2. Use 3150t free forging machine to form the blank by one upsetting and one drawing process. The upsetting ratio should reach 1 / 2. When drawing, first press it into an octagon with a small amount of reduction. The third pressing amount during drawing should be ≥20%, and the final forging temperature should be ≥800℃; 3. When it is stretched to 220mm square, press it into octagonal shape, and finally use a sling to make it into a Φ180mm circle; 4. Return to the furnace and heat at 1150±10℃ for 2h; 5. Use 1800t precision forging machine with four hammers and one fire forging, the hammer striking frequency is 90 times / min, the billet feeding speed is 20mm / s, and the final forging temperature is ≥800℃; 6. After forging to a Φ100mm circle, it is sent to a chain cooling bed for cooling to obtain titanium-containing welding wire steel bars for marine equipment that meet the surface quality and specifications.

[0057] Example 2 Preparation of Φ180mm H08MnTi welding wire steel bar for marine engineering by the method of the present invention This embodiment adopts 12t vacuum induction furnace + argon protection atmosphere electroslag furnace + 4500t free forging + 1800t precision forging to produce Φ180mm H08Mn welding wire steel bar for marine engineering, specifically: Step 1: Vacuum Induction Melting 1. Dry the chute in a heating furnace at 1100℃~1200℃, and keep it warm for more than 3h; 2. First, sandblast pure iron, metal chromium, metal molybdenum and metal nickel, and then mix according to the chemical composition: C 0.035% per furnace, Si: 0.5%, Mn: 1.40%, Cr: 0.85%, Mo: 0.65%, Ni: 0.75%, Ti: 0.065%, Zr: 0.0055%, and the rest are iron and impurity elements; 3. Install 4 Φ400mm steel ingot molds in the vacuum chamber, start to evacuate, and start to supply power when the vacuum degree is ≤10Pa; 4. Specific requirements for smelting process: First melt the charge at high power, turn to low power after the molten steel covers the bottom of the crucible, adjust the temperature to 1580~1600℃ after melting, start adding carbon blocks when the vacuum degree is ≤5Pa, and scouring for 65min under high power stirring, then fill with argon, add metal silicon, metal manganese, and ferrotitanium, and homogenize for 25min under stirring, finally add metal zirconium, and homogenize for 10min under stirring, and adjust the temperature to 1555~1565℃ for steel pouring; 5. When pouring each ingot mold, slow pouring is adopted at the beginning, with a pouring speed of 30~40kg / s. After pouring 1 / 4 of the ingot body, the rest of the ingot body is quickly poured at 60~90kg / s, and the riser pouring is poured at a slow speed of 4~8kg / s; 6. After keeping the temperature in the vacuum furnace for 240 minutes, open the furnace door and break the air; after 360 minutes, start to move the mold, and take component samples after cooling. The [O] content is 28PPm, and the [N] content is 25PPm.

[0058] Step 2: Electroslag remelting 1. Remove the iron oxide and attachments on the surface of the electrode rod, then weld two electrode rods into one electrode, and finally weld the dummy electrode; 2. Install a Φ650mm crystallizer in the electroslag furnace, prepare the slag system according to CaF2:CaO:Al2O3:TiO2=64%:20%:15%:1%, and the total slag volume is 420kg; 3. Rotate the electrode to the smelting station, then evacuate the vacuum, and start power supply after the vacuum degree is ≤20Pa; 4. Increase the current and voltage, heat the furnace temperature to 1120±10℃ to melt the slag, and the slag melting time is 60 minutes; 5. Fill the furnace with argon, increase the current and voltage, and start melting the electrode rods. The melting system is: the voltage is controlled at 80~60V, the current is controlled at 25000~12000A, the average melting speed is controlled at 7.0~9.0kg / min, and the shrinkage time is 60min; 6. During the electroslag remelting process, C powder, Al particles and Si-Ca powder are used for deoxidation, fine-tuning the composition and slowing down the burning of the original composition of the billet; 7. During the electroslag remelting process, check that the temperature of the cooling water of the crystallizer should be ≤55℃; 8. When the length of the electrode rod tail is 20mm, stop smelting, keep the furnace warm for 300min and then break the air, demould after 500min, and obtain the electroslag steel ingot with the required composition, including [O]36PPm, [N]325PPm, P≤0.0045%, S≤0.0012%.

[0059] Step 3: Forging 1. Heat the electroslag ingot. The heating conditions are: heating to 1180±10℃ at a feeding rate of ≤80℃ / s and keeping temperature for 8h; 2. Use a 4500t free forging machine to form the blank by a one-upsetting and one-drawing process, and the upsetting ratio should reach 1 / 2. When drawing, first press it into an octagonal shape with a small amount of reduction. The third time of drawing should be ≥20%, and the final forging temperature should be ≥800℃; 3. When it is stretched to 250mm square, press it into octagonal shape, and finally use a sling to sling it into a Φ210mm circle; 4. Return to the furnace and heat at 1150±10℃ for 3h; 5. Use 1800t precision forging machine with four hammers and one fire forging, the hammer striking frequency is 120 times / min, the billet feeding speed is 10mm / s, and the final forging temperature is ≥800℃; 6. After forging to a Φ180mm circle, it is sent to a chain cooling bed for cooling to obtain titanium-containing welding wire steel bars for marine equipment that meet the surface quality and specifications.

[0060] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A titanium-containing welding wire steel bar for marine equipment, characterized in that: Calculated by mass percentage, the titanium-containing welding wire steel bar includes: C: 0.03~0.09%, Si: 0.40~0.80%, Mn: 1.00~1.60%, P≤0.006%, S≤0.005%, Cr: 0.20~1.00%, Mo: 0.50~1.00%, Ni: 0.50~1.00%, Ti: 0.05~1.00%, Zr: 0.002~0.010%, [O]≤45PPm, [N]≤45PPm, and the rest are iron and impurity elements.

2. A method for preparing titanium-containing welding wire steel bars for marine equipment, characterized in that: For preparing the titanium-containing welding wire steel bar material according to claim 1, the preparation method comprises: sequentially performing vacuum induction melting, electroslag remelting, and forging to obtain the titanium-containing welding wire steel bar material, wherein: The vacuum induction melting comprises batching, vacuum induction furnace melting and pouring in sequence to obtain an electrode rod, wherein: in the batching process, according to the mass percentage of the elements of the titanium-containing welding wire steel rod, carbon blocks, metal silicon, metal manganese, metal chromium, metal molybdenum, metal nickel, titanium-iron alloy, metal zirconium and pure iron are weighed as raw materials; in the vacuum induction furnace melting process, pure iron, metal chromium, metal molybdenum and metal nickel are loaded into the vacuum induction furnace, and power melting is started when the vacuum degree is ≤10Pa, and the temperature is adjusted to 1580-1620°C after melting, and carbon blocks are added when the vacuum degree is ≤5Pa, and the refining time is ≥30min under stirring conditions, and then inert gas is filled, and metal silicon, metal manganese and titanium-iron alloy are added, and the homogenization time is ≥10min under stirring conditions, and finally metal zirconium is added, and the homogenization time is ≥5min under stirring conditions to obtain an alloy melt; in the pouring process, the alloy melt is poured into an electrode rod, The electroslag remelting smelting includes sequentially performing electrode rod surface treatment and protective atmosphere electroslag remelting smelting to obtain electroslag ingots, wherein: during the electrode rod surface treatment process, the electrode rod surface is polished; during the protective atmosphere electroslag remelting smelting process, a CaF2-CaO-Al2O3-TiO2 slag system is used, the slag heating temperature is 1050-1300°C, the slag time is 40-90min, the voltage is controlled at 100-40V, the current is controlled at 30000-8000A, the average melting rate is controlled at 5.0-10.0kg / min, and the shrinkage feeding time is ≥30min. The forging process includes sequentially performing electroslag ingot heating, blank forming, furnace heating, fine forging and air cooling to obtain the titanium-containing welding wire steel bar, wherein: during the electroslag ingot heating process and the furnace heating process, the heating temperature is 1100-1250°C, and the insulation time is calculated according to the diameter of the electroslag ingot; during the blank forming process, a one-upsetting-one-drawing process is adopted, and the final forging temperature is ≥800°C; during the fine forging process, the final forging temperature is ≥800°C.

3. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: Before the vacuum induction furnace smelting process, the chute is heated in a heating furnace at 1100~1200℃, and the insulation time is greater than 3h; before the batching process, the pure iron, metal chromium, metal molybdenum and metal nickel are sandblasted.

4. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: During the smelting process in the vacuum induction furnace, after the power is supplied for smelting, the charge is first melted at the first power, and the second power is switched after the molten steel covers the bottom of the crucible. The first power is greater than the second power. During the smelting process in the vacuum induction furnace, the vacuum degree is ≤5Pa. During the smelting process in the vacuum induction furnace, the total refining time is ≥1h.

5. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: During the pouring process, the pouring temperature of the electrode rod is 1550~1580℃, the pouring speed at the beginning of pouring is 20~50kg / s, after pouring 1 / 4 of the ingot body height, the remaining ingot body is poured at a pouring speed of 50~100kg / s, and the riser pouring is poured at a pouring speed of 2~10kg / s; after the pouring is completed, the air breaking and demolding treatment are carried out, the air breaking time is ≥100min, and the mold moving time is ≥240min.

6. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: In the CaF2-CaO-Al2O3-TiO2 slag system, the mass ratio of each substance is: CaF2:CaO:Al2O3:TiO2 is 64%:20%:15%:1%.

7. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: During the protective atmosphere electroslag remelting smelting process, C powder, Al particles and Si-Ca powder are used for deoxidation, fine-tuning the composition and slowing down the burning of the original composition of the billet; during the protective atmosphere electroslag remelting smelting process, the temperature of the cooling water of the crystallizer is ≤55℃; after the protective atmosphere electroslag remelting smelting is completed, breaking and demolding treatment are carried out, the breaking time is ≥120min, and the moving mold time is ≥360min.

8. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: During the heating process of the electroslag ingot, the heating rate is ≤80℃ / s, and the holding time is calculated according to the following formula: T=KD, where K is the holding time coefficient, which is 0.1-1.5, and D is the diameter of the electroslag ingot; the heating temperature and holding time of the reheating process are the same as the heating temperature and holding time of the electroslag ingot heating process.

9. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: During the blanking process, the upsetting ratio is greater than 3.5, and the reduction in at least one pass during drawing should be ≥20%.

10. The method for preparing titanium-containing welding wire steel bar for marine equipment according to claim 2, characterized in that: During the precision forging process, four-hammer deformation is adopted, the hammer striking frequency is ≥90 times / min, and the billet feeding speed is ≤25mm / s; the cooling process is carried out in a chain cooling bed.

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